Chemoselective Catalytic Oxidation of 1,2-Diols to α-Hydroxy Acids Controlled by TEMPO–ClO2 Charge-Transfer Complex
摘要:
Chemoselective catalytic oxidation from 1,2-diols to a-hydroxy acids in a cat. TEMPO/cat. NaOCl/NaClO2 system has been achieved. The use of a two-phase condition consisting of hydrophobic toluene and water suppresses the concomitant oxidative cleavage. A study of the mechanism suggests that the observed selectivity is derived from the precise solubility: control of diols and hydroxy acids as well as the active species Of TEMPO, Although the oxoammonium species TEMPO+Cl- is hydrophilic, the active species dissolves into the organic layer by the formation of the charge-transfer (CT) complex TEMPO-ClO2 under the reaction conditions.
作者:Robert-André F. Rarig、Matthew Scheideman、Edwin Vedejs
DOI:10.1021/ja800402g
日期:2008.7.1
Metal-free homoallylic oxygen-directed intramolecular hydroboration is reported. Regioselectivities from 20:1 to 82:1 favoring the 1,3-dioxy-substituted products have been achieved using Me2S center dot BH3/TfOH followed by standard oxidative workup. Branching at the C5 position improves regioselectivity.
Glycolipid derivatives, process for production of the same, intermediates for synthesis thereof, and process for production of the intermediates
申请人:Japan as represented by President of National
Center of Neurology and Psychiatry Ministry of
Health